Sierra Streams Institute and Sierra College will host a discussion "Sediment and Mercury Loads from Creeks to Reservoirs: A Golden Opportunity," a presentation by Dr. Carrie Monahan, science director at The Sierra Fund, on Tuesday, Oct. 10.

Monahan will speak about the impact of mercury in waterways as a result of hydraulic and hard-rock mining. During the California Gold Rush era, over 10 million pounds of mercury were used in mining, and it is estimated that 10-30 percent of liquid mercury was lost to the environment, according to a news release.

"Mercury has caused many health and environmental problems, as it contaminates river gravels containing hydraulic mining debris and is integrated into the aquatic food web," the release states. "For over 30 years, sand miners and irrigation districts have removed mercury-containing sediments that have accumulated in water-supply reservoirs such as the Combie Reservoir."

The presentation will be held from 6:30-7 p.m. in the Sierra College Multipurpose center, building N-12, though guests may arrive at 6:30 p.m. for a meet-and-greet and refreshments. The event is free of charge, but campus parking permits are $3 and can be purchased at the kiosk machine at the main entrance to Sierra College.

The Combie Reservoir Removal project will excavate mercury-contaminated sediment from the Combie Reservoir and implement an innovative recovery process to remove mercury from the material. According to the release, the project will remove and treat around 135,000 cubic yards of sediment from the upstream reach of the Combie Reservoir.